Multiple drum centrifugal



May 7, 1940. 'r. A. BRYSON v MULTIPLE DRUM CENTRIFUGAL Filed Aug. 2, 1935 //v yaw 7-0;? ZZINDYAI ZHYSUN ,4 7* 70km: Y

Patented May 7, 1940 UNITED STATES PATENT OFF-ICE 9 Claims.

My invention relates to improved feeding means for centrifugal machines of the sedimentation type for the treatment of liquid material, and

particularly, but not exclusively, to those in which two or more rotatable drums of different size and different separating capacity are coaxially arranged in nested relation, and to which the material to be treated is fed in parallel.

As pointed out in my copending application Serial No. 653,271, filed January 24, 1933, it is quite essential that the material treated in each drum of a multiple drum centrifugal machine of this type be subjected to substantially the same force-time effect. Where the drums are nested one within the other, they are naturally of different diameter and the centrifugal force-effect decreases from a maximum in the outer drum to a minimum in the inner drum. This being so, the material must be subjected to treatment for longer periods of time in the inner drums than in'the outer drum. The relative separating capacities of a plurality of drums of different diameters and rotating at the same number of revolutions per minute are in accordance with the squares of their respective radii. This being so, the material to be treated should be fed to the drums at different rates and in accordance with this rule.

One of the objects of my invention is to provid a simple feeding means whereby material withdrawn from a common source of supply will be positively fractionated and delivered to the respective drums at rates proportional to their separating capacities. A further object is to provide a feeding means which will positively accelerate the material in the direction of drum rotation so that when it reaches the drums itwill already have a high circumferential velocity thus leaving much less of the work of acceleration for .the drums to do. This means that there will be less scour in the drums, the average rotative speed of stock within the drums will be increased, and hence more centrifugal force will be applied to the stock, and the separation will be conducted more efliciently. In other words, bysubjecting the stock in the drums to a greater centrifugal force than is now possible with present types of feed, the stock may be passed through the drums at higher velocity and yet be subjected to the same force-time efiect. Hence, a higher feed rate can be maintained and the separating capacity of the unit thereby increased.

. With these objects in view my invention includesthe novel elements and the combinations andarrangements thereof described below and illustrated in the accompanying I drawing, in which- Fig. 1 is a fragmentary elevation, partially in section, of my machine;

Fig. 2 is a bottom plan view of the interior of a frusto-conical element formingpart of the feeding means;

Fig. 3 is a fragmentary development showing the inside surface of the frusto-conical element illustrated in Fig. 2; I

Fig. l is a fragmentary section through the feed assembly in the plane 4-4 of Fig. 2;

Fig. 5 is a fragmentary section through the feed assembly in the plane 5-5 of Fig; 2; and,

Fig. 6 is a fragmentary section through the feed assembly in the plane 6-6 of Fig. 2.

Referring to the drawing, centrifugal machines to which my feeding means is applicable generally comprise an outer stationary casing I and a circumferential gutter or trough 2 into which the treated material is discharged. Rotatably mounted in suitable bearings 3 and 4 in the central portion of the casing l v is a spindle 5 driven by means of a pulley 6 and the belt or rope '1. Secured to the upper portion of the spindle and rotatable therewith is a frusto-conical hub 8,.the bottom of which is carried out horizontally, as shown at 9, and serves to support the drum assembly. The outer drum is shown at I 0, the intermediate drum at H, and the inner drum at 12.

The outer drum may be supported directly on the horizontal lip 9 as shown at H; the intermediate drum may be supported on projections I4 so that its bottom is raised somewhat above the level of the bottom of drum l 0; and the innermost drum 12 may be supported on a perforated baffle 15 secured within drum II, and so that its bottom is positioned at a somewhat higher elevation than the bottom of the intermediate drum II. The drums may be held in spaced, concentric relation, coaxial with the spindle 5, by any appropriate means, but are preferably maintained in this relative relation by the ribs 40 andthe baffles 15, as shown. At the bottom, theainnermost drum I2 is provided with an inwardly projecting lip IS, the intermediate drum is provided with a similar lip l1, and the bottom 9 of the hub 8 forms the equivalent of an inwardly projecting lip for the outer drum I0. At the top, each of the drums is provided with an inwardly projecting lip as shown at l8, l9 and 20, audit is to be noted that the elevation of the tops of the drums increases from the outer to the inner drum so that the material may be discharged over the tops of the inner drums without interference.

Coaxial with the spindle 5 and the frustoconical hub 8, is an outer frusto-conical shell or element 2| spaced from the hub 8 to provide therebetween a passage for the flow of material to be treated. The space between the frustoconical elements 8 and 2| is subdivided into a plurality of vertically extending ducts 22 by means of a plurality of circumferentially spaced vanes 23. These vanes 23 extend from the top of the outer frusto-conical element to the bottom thereof and may be secured thereto by rivets or other means, as shown at 24. Preferably, these vanes are not elements of the frusto-conical surface 2| but are made in spiral form as shown in Figs. 2 and 3; it being understood that the upper ends of the spirals are further advanced, in the direction of rotation, than the bottoms of the spirals. In other words, the bottoms of the vanes trail the tops thereof as the device rotates. A common feeding cone or funnel 25 having a depending cylindrical portion 26 receives all of the material to be treated and discharges it into the ducts between the frusto-conical members. As the liquid material passes outwardly in contact with the upper portions of the vanes 23, it is not only picked up thereby and rapidly accelerated in the direction of rotation of the drums but is actually displaced downwardly and driven into the ducts between the frusto-conical elements.

Since the separating capacities of the drums are not equal, it follows that the flow capacity of the ducts must be proportioned to conform to the separating capacities of the respective drums which they feed. In Fig. 2 I have shown twelve ducts, four of which 21 are arranged to discharge into the outermost drum through the orifices 32 at the bottom. These are the largest 'ducts and the discharge orifices which will be later described are distributed symmetrically about the axis of rotation. Similarly, the ducts.

28 have the lowest flow capacity and are arranged to discharge into the innermost drum through orifices 29 which are likewise symmetrically disposed 90 apart about the cone 2|. The

flow capacity of the intermediate ducts 39 which feed the middle drum is, of course, intermediate the flow capacities of the ducts feeding the inner and outer drum, and the discharge orifices 3| therefor are'symmetrically disposed about the periphery of the cone 2|.

It will be observed from a consideration of Figs. 2, 3, 4, 5 and 6 that the discharge orifices 29, 3| and 32 are arranged at difierent levels.

The outer conical shell 2| may terminate at the of the intermediate drum ring 37! is secured to the conical element 2| at bottom at the proper elevation so that material and at an elevation somewhat above the portion 9 which forms the inwardly projecting lip at the bottom of the outer drum. A spinner ring 36 is secured to the frusto-conical element 2| at the bottom of the orifices 3| and the top of this spinner ring is at a somewhat higher elevation than the top of the inwardly projecting lip ll Likewise a spinner the bottom of the orifices 29 and the top of this spinner ring is at a somewhat higher elevation than the top of the inwardly projecting lip |6 of the innermost drum.

From the foregoing it will be apparent that as the material is discharged from the common feeding means 25 into the space between the frusto-conical elements 8 and. 2| the total supply will be positively divided or fractionated, by

means of the vanes 23, into a plurality of separate streams which, in turn, are subdivided into groups so that each group feeds one of the drums. By properly proportioning the fiow capacities of the ducts between the frusto-conical elements, the material fed to the machine will be positively fractionated and delivered to the various drums in accordance with their respective separating capacities. in the space between the frusto-conical elements the liquid material will be rapidly accelerated in the direction in which the drum assembly is rotated so that as it is delivered from the oriand drive it into thespace between the cones.

I also find that if the'vanes arecurvedroughly in accordance with the path' which the material would take if the vanes were omitted,.un-

necessary turbulence is avoided .and the possibilitypf the formation of eddies where fiber may be deposited andbuilt up eventually to clog the duct is minimized.

bottom portions of the vanesat an angle of not I Italso:prefer to leave the less than about 15 to the cone elements rather than attempt to push the stock around to a complete vertical flow.

From the foregoing, it .will be apparent that the advantages to be derived from .usingmyinvention are not confined solely to its application to a multiple drum type of machine. .Since .the

"separating efficiency of eachdrum in the assembly-is increased. it follows that the separating efficiency .of any: single drum "machine maybe in creased by 'using impeller vanes in a conical feeding duct, whereby the stockpassing therethrough is positivelyaccelerated in-the direction "of rotation of the drum and delivered-to the drum witha high circumferential velocity, thus reducingscour and increasing the-average centrifugal force acting upon the stock during the time it is in the drum.

I While I have described my invention inits preferredembodiments, it is to-be understood that thewords which I have used -are words of description rather than of limitation. Hence, changes within the purview of the appended claims'may' be'made without departing from thetrue "scope and spirit of "my invention in its broader aspects.

'What Iclaim is:

1. In a centrifugal machine of the sedimentation type for the treatment of liquid material, "the combination with a'plurality of rotatable drums of different size and different separating Q'capacity coaxiallyassembled in nested relation, one within the other, of means within said'drum' assembly and rotatable therewith'towhich' the Due to the presence of the vanes 23.

"but, because of their inclination to the vertical, they will actually displace the stock downwardly material to be treated is delivered and through which it is passed for delivery to said drums, and means within said first mentioned means for positively fractionating said material between said several drums in accordance with their respective separating capacities.

2. In a centrifugal machine of the sedimenta itively fractionating. said material between said several drums in accordance with their respective separating capacities.

3. In a centrifugal machine of the sedimentation type for the treatment of liquid material, the

combination with a plurality of rotatable drums of different size and different separating capacity coaxially assembled in nested relation, one with in the other, of two conical shells coaxial with .said drums and arranged in spaced nested relation within said drum assembly to form a rotatable conical duct therebetween for the passage to said drums of material to be treated, and circumferentially spaced means within said duct for positively fractionating said material between said drums in accordance with their respective separating capacities.

4. In a centrifugal machine of the sedimentation type for the treatment of liquid material,

the combination with a plurality of rotatable drums of different size anddifferent separating capacity coaxially assembled in nested relation, one within the other, of means within said drum assembly and rotatable therewith through which the material to be treated is passed for delivery to said drums, and means within said first mentioned means for positively accelerating the material in the direction of rotation of the drum assembly and simultaneously fractionating said material between said several drums in accordance with their respective separating capacities.

5. A centrifugal machine of the sedimentation type for the treatment of liquid material comprising a plurality of rotatable drums of different size and different separating capacity coaxially assembled in nested relation, one within the other, rotatable means within the innermost drum coaxial with said drum assembly and forming a plurality of separate, circumferentiallyespaced vertically-extending ducts having symmetrically spaced discharge orifices at their bottoms, and means for supplying untreated material to said ducts at the upper ends thereof; said ducts being arranged in a plurality of groups with each group discharging into a separate drum; and the relative flow-capacities of said groups being in accordance with the relative separating capacities of the respective drums fed therefrom,

6. In a centrifugal machine of the character described, comprising a plurality of nested drums rotatable about a common vertical axis and provided at their bottoms with inwardly projecting lips adapted to retain in said drums material undergoing treatment, means for supplyin material to be treated to said machine, and rotatable means Within the innermost of said nested drums forreceiving all said material and thereafter positively fractionating it and simultaneously delivering it to each of said drums at rates proportional to their respective purifying capacities.

7. In "a centrifugal machine of the sedimentation type for the treatment of liquid material, the

} combination with a plurality of rotatable, imperforate drums of different size and different separating capacity coaxially assembled in nested relation, one within the other, of means within said separating capacities; of a common means for feeding material to said ducts. 1

9. In a centrifugal machine of the parallelfeed-discharge type comprising a plurality of nested drums, means for feeding untreated material to said drums comprising an inner frustoconical member, an outer frusto-conical member and a plurality of circumferentially spaced vanes between said members forming a plurality of ducts open at the top to receive untreated material from a common source of supply; said ducts being divided into a plurality of groups, one for each drum; each group discharging into a separate drum through openings provided at the bottom of said ducts; and the relative flow-capacities of said groups being proportioned to the respective separating capacities of the drums into which they discharge.

, 'IANDY A. BRYSON. 

